<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>css选择器</title>
	<style>

		div{
			color:red;
		}
		#div1{
			color: blue;
		}

		.big{
			font-size: 40px;
		}
		.green{
			color: green;
		}
		.link{
			font-size: 40px;
			text-decoration: none;
			color: green;
		}

		.link:hover{
			color: gold;  
		}

	</style>
</head>
<body>
	<div id="div1" class = big>类元素</div>
	<div class = green>这是第二个div</div>
	<h1>=================伪类和伪元素选择器=======</h1>
	<a href="www.baidu.com" class="link">百度 </a>
	<br>
	<br>
	<h1>===================================盒子模型=============================</h1>
</body>
</html>